Methods of applying bearing members to bodies



P 9, 1969 w. G. cHEARY 3,465,404

METHODS OF APPLYING BEARING MEMBERS TO BODIES Filed NOV. 30, 1966 United States Patent 3,465,404 METHODS OF APPLYING BEARING MEMBERS T0 BODIES Walter Graham Cheary, Birmingham, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England, a British company Filed Nov. 30, 1966, Ser. No. 597,996 Claims priority, application Great Britain, Dec. 6, 1965, 51,617 65 Int. Cl. B21d 53/10; B23k 31/02 US. Cl. 29149.5 4 Claims ABSTRACT OF THE DISCLOSURE The application of a bearing member of one material to a body of a different material in which an oversize billet approximating the shape of the intended bearing member is placed in a position which the bearing member will occupy respecting the body and a refractory member supports the billet at least at the side remote from that to be applied to the body. The assemblage is heated above the melting point of the billet material but below that of the body material for bonding the billet to the body. After cooling the assemblage, the refractory member is removed and the exposed surface of the billet is finished to provide a bearing surface.

This invention relates to methods of applying bearing members of one material to bodies of a different material. The methods are suitable, for example, for applying sleeves to bores or for applying thrust bearing surfacing members to bodies.

The object object of the invention is to provide a method of applying bearing members to bodies which is effective and relatively inexpensive.

According to the present invention, a method of applying a bearing member to a body, with the melting point of the material of the bearing member being substantially below that of the material of the body comprises the steps of preparing an oversize billet approximating to the shape of the intended bearing member, placing the billet in a position which the bearing member is intended to occupy with respect to the body, supporting the billet at least at the side thereof remote from that side which is intended to be applied to the body with a refractory member, heat ing the assembled body, billet and refractory member to a temperature above the melting point of the material of the billet, but below that of the material of the body to bond the billet to the body, cooling the body, billet and refractory member, removing the refractory member, and finally finishing the exposed surface of the billet to form a bearing surface on the bearing member.

The invention will now be described by way of example with reference to the accompanying drawing, the single figure of which is a cross-sectional view of a hydraulic pump rotor to which the invention is applied.

This example applies to a cylindrical hydraulic pump rotor which is to be formed with a plurality of angularly spaced parallel bores, only one being shown, each of which is to be provided with a sleeve. The bores are stepped in the finished rotor and only the wider portion is to be sleeved, and this wider portion terminates at one end of the rotor.

At the opposite end of the rotor there is to be applied a bearing surfacing member to which, in the finished rotor, the smaller ends of the bores will extend.

At the early stage of production illustrated in the drawing, however, the rotor has bores 11 which are only formed over their larger diameter portions and the flat end face of the rotor against which the bearing surfacing member is to be applied is only provided with for in- Patented Sept. 9, 1969 stance, three small spaced holes, which are aligned with three of the bores 11, respectively.

In this example, the rotor is of steel and the sleeves and bearing surfacing member are of Phosphor bronze.

The application of the sleeve to the rotor 10 is carried out simultaneously with the application of the bearing surfacing member to the rotor end face.

The method for applying the same comprises preparing a plurality of tubular billets 12 approximating to the shape of the intended sleeves, with the billets being oversize by providing that the internal diameters of these billets 12 is substantially less than those of the finished article and the lengths of the sleeves being such that, as shown, the ends extend beyond the bores 11 respectively.

There is also prepared a flat billet 13 to serve as the bearing surfacing member, this with being oversize, both in diameter with respect to the rotor 10 and also being thicker than is required for the eventual member, The billet 13 has three spaced holes for reception of pegs 14 for locating the billet 13 in relation to the end face of the rotor 10. The billets 12 and 13 are now placed in their respective positions so that in the case of each billet 12, the external surface is substantially in contact with that of the interior of the associated bore 11, and in the case of the billet 13, the adjacent sufraces of the billet and rotor are in contact.

The interiors of the tubular billets 12 are then filled with respective refractory members which, in this example, are foundry sand cores 15 which are formed by pouring sand into the bores as a liquid slurry. This is compacted and cannot run out since the ends of the bores 11 are closed. A lipped refractory tray 16 is placed beneath the billet 13 and, as shown, the lip of the tray 16 is spaced from the external cylindrical surface of the rotor 10.

A weight 17 is then applied to the ends of the billets 12 and to an upstanding edge 18 of the rotor 10, and the weight -17 has a coating of a material to which the bronze of the billets 12 will not readily adhere, such as nickel aluminide. The whole assembly is placed in a furnace and the temperature is raised to a value above the melting point of the bronze billets 12, 13 but below that of the steel rotor 10. The billets will melt and a bond will be formed between the steel and the bronze. In the present example the temperature is in the range of 1130 C. with a tolerance of 10 C. above or below this value.

The assembly is then cooled and the refractory materials removed by breaking out the sand and by removing the tray 16. Finally, the exposed surfaces of the billets 12, 13 are machined to form bearing surfaces.

A suitable refractory material for filling the bores is a clean silicon sand containing 10% to 18% sodium silicate, 10% to 18% calcium silicate and water with possibly other substances, with the curing being by heat. It will, however, be realized that the refractory material for the bores of the billets 12 may be preformed as is the tray 16. It is desirable that the refractory in the billet bores should be located concentrically within the bores 11 in the rotor 10 so that any tendency towards eccentricity of the bronze should be minimized. Other requirements for the refractory materials are that it should not be wetted by molten bronze in the temperature range specified, it should be self-supporting at these temperatures, and it should not react with the molten bronze.

Phosphor-bronzes which have been found to be satisfactorily applied by the method described have a 5% or 7% tin content.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A method of applying a bearing member to a body, with the melting point of the material of the bearing member being substantially below that of the material of the body, which comprises the steps of preparing an oversize billet approximating to the shape of the intended bearing member, placing the billet in a position which the bearing member is intended to occupy with respect to the body, supporting the billet at least at the side thereof remote from that side which is intended to be applied to the body, with a refractory member, heating the assembled body, billet and refractory member to a temperature above the melting point of the material of the billet, but below that of the material of the body to bond the billet t0 the body, cooling the body, billet and refractory member, removing the refractory member, and finally finishing the exposed surface of the billet to form a bearing surface on the bearing member.

2. The method as claimed in claim 1 in which the billet is subjected to pressure during the steps of heating the assembly to the required temperature.

3. The method as claimed in claim 1 in which the billet is in the form of a sleeve which is inserted into a bore References Cited UNITED STATES PATENTS 2,270,486 1/1942 Willi 29-1495 2,649,651 8/1953 Townhill 29149.5 2,690,004 9/1954 Crawford 29423 3,149,405 9/1964 Dolan 29149.5

THOMAS H. EAGER, Primary Examiner US. Cl. X.R. 29529 

